Spark-plug



0.,.L. L0NGwomH.

SPARK PLUG.'

APPLICATION FILED SEPT- 27, 1919.

1,350,319, PndAug. 24,1920.

` 'Be it known that I,

uifur'i-:D STATES Finca.

` ons L'. LoNGwoRTH, or nn'rnoi'r, MICHIGAN, .sesiones or cnn-HALF To n. 1:..

' Mesem/110K, or na'rncrr, niermann.

' spank-PLUG.

Zo all whom z't may' concern:

h O Tis L.. LoNGwoR'rH, a citizen of the United States oi America, residing at Detroit, in the county of lJVayne and State of Michigan, have invented certain new and useful Improvements in Spark-Plugs, of which the following is a specification, reference being had therein ,to the accompanying drawings.

This invention relates to spark plugs and its object is to provide a spark plug having a spark gap located within a chamber, which may be formed by the casing of the plug and which will protect the electrode forming said gap from such drops of lubricating oil as may be thrown ofi" from the piston of the engine.

A further object of the invention is to provide a spark plug having two spark gaps one of which is formed between the end portion of the usual central electrode and a hood portion of the casing of the plug, the second gap being formed within a chamber of the casing partially closed by said hood, the hood acting additionally to shield the electrode of said second spark gap from such lubricating oil as may be thrown oft' from the piston of the engine, so that when the first mentioned gap becomes inoperative by reason of said oil the gap Within said chamber will come into 'use A preferred embodiment of the invention is hereinafter described as illustrated ip the accompanying drawings.

vI4`igure 1 is an axial sectional View 'of the improved plug; Fig. 2 is an end view of the same.

In these viewsthe reference character A. designates the porcelain of the plug, B the stem passing through said porcelain and forming a central electrode and C the casing Within which said porcelain is secured. A spark gap D is formed between a reduced end portion E of thestem B and a hood lC ot' approximately semi-spherical shape upon the inner end of the casing C vand preferably integral with said casing, The aperture ot' i"c hood l" forming said gap is circular so that there are innumerable points at which the spark may cross said gap. Thus the possibility of fouling of the electrodes by carbonization or lubricating oil. is minimized. Between the hood l" and porcelain A there is formed a chamber G, to which the gases in the combustion chamber (not Specification of Letters lfatent. Patentd Aug 24, 1920. tpncation mea september e7, i919. serial No. 326,839.

shown) have access through several orifices H in the h'ood F, as well as through the gap D. Within said chamber a second spark gap J, slightly wider than' the gap D, is

formed between the casing C and an electrode K formed as a coliar upon the stem B and preferably integral withsaid stern.

In the operation of the described invention the spark will occur at the gap D ifthe electrodes forming' said gap are vnot fouled by a lubricating oil, since this/gap4 its relatively large diameter, even if lubrieating oil penetrates to some extent to the chamber G, it is altogether improbable that the electrodes forming the gap J will be completely fouled by such oil. Because of the periodic rush of gases to and from the chamber G, tl'iere can be-no accumulation of carbon upon the electrodes forming either of the two spark gaps. p

While the described spari'L` plug is highly advantageous 'for use upon any engine, since it minimizes ignition trouble, it has a peculiar adaptation to engines possessing the defect commonly known as oil pumping. In such engines the )istons have a tendency to continually t row oii' lubricating oil and spark' plugs of the ordinary single gap type are thus soon rendered inoperative. lf the'above described plug be used with such engines, however, the oil will et feet only the gap l) and as soon as the spark is prevented from crossing said"gap, the protecte(4 gap J will come into use,

W hat l claim as 'my invention is:

1. A spark' plug having a chamber and openings thereinto of small area as compared to that of the'chamber and having two spark gaps, one of which isformed within. said chamber and the other in one of said openings communicating with the chamber.

2. A spark plug comprising an insulating body, a casing receiving said insulailf-v body, said casing forming a chamber at ein end of the insulating body having an opening into the same of small' area ascompared to that of'the chamber, and an electrode passing through the insulating body Jforming With said electrode tWo spark gaps, one of Which is located Within said chamber and protected by such location from lubricating oil and the other of Which is in the Wall of i said chamber.

. 3. A spari; plug comprising an insulating body, a casing receiving said insulating body forming a chamber at one end of said lsaid chamber and is protected from lubrieating oil by such location and the other of 20 which is in one of saidopenings of theyhood. In testimony whereof aixmy signature.

oris L. LoNeWon-.TH 

